I'm not sure you have to update the copyright every year for any particular reason. Anyone know?

I know, and you don't have to. (Actually, you don't even need the copyright notice at all -- copyrights are valid without it -- but it's a good idea anyway.)

In fact, you shouldn't update it. If you write something in 2002, someone steals the code in 2005, and in 2007 you change the copyright to read "copyright 2007", then later it becomes an issue, the person who stole it can claim "Look, my version is earlier!" and you'll have to go through the explanation of what happened and perhaps provide proof of it, which is an argument you wouldn't have had to make if you'd just left the copyright notice alone.

I guess I just use it as a proxy to show how long the site has been up. I use a range in the footer on that project:

© Copright 2006-2010

Probably dumb but I do find myself looking in the footer of sites to see how active it is.

We do this, but make the later date dynamic. So it will always say Copyright <year>-<current year>

Is that legal? If you don't make any changes the copyright date shouldn't change.

Since those notices aren't required, I don't know whether they have any legal status at all.

Theoretically, the copyright date tells you when the copyright will expire: a work Copyright 2000 will become public domain ten years sooner than one Copyright 2010. However, since neither of those seem likely to ever expire in the first place, this mostly only matters with very old works (around the start of last century).